@liamwhite1 (Insert Lucy (2014) theme here)

@liamwhite1 As it turns out, Trisquel has its own theme… called Trisquel.

@Parcly Taxel  
As a full-time Linux user I was surprised that you did not know what I meant by a GTK theme.
 
Certain desktop environments have different default GTK themes. GNOME, for example, primarily uses Adwaita:  
 
If you like your gtk3 darker gnome-tweak-tool also has an option to use dark Adwaita as the default theme.
 

 
Ubuntu by default uses the Ambiance theme (which is slightly broken here because I built the binary against gtk3, and Ambiance for gtk3 has not been updated to the latest version).
 

 
What theme are you currently using?

@liamwhite1 Theme? This is Trisquel using the GNOME interface.

What’s the name of that GTK theme?